1. Bring water to boiling point and and keep
water at low heat. Combine lemon juice and sugar in a pot under double boiler
and stir until sugar dissolved.

2. Remove lemon juice from heat. Crack eggs
into a separate bowl or cup, lightly beaten and stir in the eggs a little at a
time until combined and add lemon zest into it. Bring the pot back under double
boiler and stir continuously for 5-6 minutes (mine was around 12 minutes),
until thickened. （I cooked it at low heat until thickened ） .

3. Strain the hot cream and stir in butter till
butter melted and mix well . Pour into clean jar and allow to cool before
putting it in the fridge.